Rotatable cylinder plating rack



L. W. RAYMOND ETAL ROTATABLE "CYLINDER PLATING RACK Filed Aug. 22, 1960 s Shets-Sheet 1 INVENTORS LOUIS W. RAYMOND ROGER E. REATH Quint E-m-ond, ATTORNEYS Oct. 22, 1963 L. W. RAYMOND AL ROTATABLE CYLINDER PLATING RACK 3 Sheets-Sheet 2w Filed Aug. 22, 1960 I J In N INVENTORS LOUIS W. RAYMOND BY ROGER E. REATH QM alumna) HMOM'M ATTORNEYS Oct. 22, 1963 Filed Aug. 22, 1960 FIG. 3

FIG. 4

L. w. RAYMOND ETAL ROTATABLE CYLINDER PLATING RACK 3 Sheets-Sheet 3 LOUIS W. RAYMOND BY ROGER E. REATH Uite This invention relates to a rotatable rack for use in electroplating operations. More particlarly it relates to a rotatable rack having a bipolar electrically conductive axle and an anode which is particularly designed for uniform deposition of metal on the inner walls of cylinders.

I-n electroplating operations it is desirable to electroplate a number of workpieces simultaneously and to do so with a minimum amount of handling. The present invention provides a rotatable plating rack on which is possible to plate a plurality of workpieces and which eliminates all handling of the workpieces except for loading and unloading operations. The new rack further provides for receiving and maintaining cylinders in proper relationship with an anode of such design that a metal surface of the desired quality can be deposited on the inner wall of the cylinder.

The rotatable plating rack of the present invention which is adapted for use in combination with a bath of electrolyte to plate at least one workpiece has a bipolar electrically conductive axle which is rotatable within stationary bearings. A bracket assembly is rigidly attached on and electrically connected to one of the poles of the axle and is rotatable with the axle. At least one anode is mounted on the bracket assembly in such position that it is submerged into and emerged from the electrolyte as the axle is rotated. The anode is insulated from the bracket assembly .and is electrically connected to the other pole of the axle by electrical conductor means. The work-piece is also mounted on the bracket assembly in electrical contact therewith and means are provided for rotating the axle.

A preferred embodiment of the invention is described hereinbelow with reference to drawings, wherein FIG. 1 is a side elevation of a rotatable plating rack in its loading position taken along lines 1-1 of FIG. 2;

FIG. 2 is a plan of the rotatable plating rack;

FIG. 3 is an elevation partly in section of an anode as mounted on the plating rack;

16. 4 is a front elevation of the plating rack in its operating position rotated 180 from the position shown in FIG. 1.

Referring initially to FIG. 1 and FIG. 4, a rotatable plating rack It} is shown securely mounted on the flanged edges 11 of a tank 12 by means of bearings 13 and 13 which are secured to the edges of the tank. The tank 12 contains a suitable bath of electrolyte 1 4 the chemical constitution of which depends upon the metal to be deposited but which in the instant embodiment it chromium. The rack 16 is rotatable on a bipolar axle 15 which extends horizontally across the tank with a portion near each end disposed within the bearings 13- and 13'.

The axle 15 is substantially an elongated rectangular bar which is formed by laying a plurality of elongated rectangular metallic plates 16 horizontally one on top of each other, and separating them at their mid-point by inserting an electrically nonconductive insulating plate 17 of width equal to the metallic plates. Extending vertically through the axle 15 are a plurality of nut and bolt assemblies 18 which serve to maintain the metallic plates 16 and the insulating plate 17 tightly secured together. The nut and bolt assemblies 18 can consist of an insulating sleeve extending vertically through the axle 15 through which a bolt will extend, and have insulating washers disposed between the nut and each pole of the axle 15. Or alternatively the nuts and bolts may be constructed from a resinous plastic material. Of course any other suitable means may be used as long as the axle 15 is securely held together without permitting any current transfer between the separated metallic plates '16.

Referring now to FIG. 4, the axle 15 has been divided by the insulating plate 17 into an upper portion 19 and a lower portion 20. The upper portion 19 is intended to be connected to the negative terminal 21 of a suitable source of electricity and thereby causes the upper portion '19 to become the negative pole. Conversely the lower portion 20 of the axle 15 is intended to be connected to the positive terminal 22 of the same source of electricity and it thus becomes the positive pole of the bipolar axle 15.

Referring now to FIG. 1 as well as FIG. 2, plastic journals 23 are formed about that portion of the axle 15 which is disposed within the bearings 13 and 13'. The plastic journals 23 tightly encompass the axle 15 and are rotatable therewith. The outer surface of each journal 23 is cylindrical in shape such that they turn freely within the bearings 13 and 13' and promote smooth rotation of the axle 15. The plastic from which the journal 23 is formed is electrically nonconductive, thereby incuring that current will not be transferred from the axle 15 to the bearings 13 and 13 or between the poles of the bipolar axle 15.

A plurality of substantially U-shaped brackets 25 are secured to the positive pole 19 of the axle 15 and depend therefrom for a substantial distance. The brackets 25 as best shown in :FIG. 1 include a transverse section 26 mounted on the negative pole 19' of the axle 15 (in FIG. 1 the axle has been rotated from the position shown in FIG. 4) by suitable attaching means 27 and extending transverse relative to the longitudinal extension of the axle 15. Rigidly attached to each end of the transverse section 26 and extending normally therefrom to complete the substantially U-shaped brackets 25 are perpendicular sections 28 and 28'. The perpendicular sections 28 and 28 are secured to each end of the transverse section 26 and are maintained in their normal position by attaching means 29.

Secured to two of said transverse sections 26 by means 31 and extending substantially normal therefrom (as shown in FIG. 4) are L-shaped supports 32 and 32'. Mounted on the ends of the supports 32 and 32 and secured thereto by attaching means 34- and 34' is a counterweight 36. The counterweight 35 extends parallel to the axle 15 and is of such a weight as to counterbalance the weight of the apparatus and workpieces disposed on the ends of the perpendicular supports 28 and 28' where the rack is loaded and thereby aid in its rotation. The counterweight 36 also serves as a stabilizer for the apparatus when the workpieces are unloaded and due to the weight of the counterweight 36 it maintains the rack in its upright position.

Referring now to FIG. 2, secured to the upper end of each of the perpendicular sections 28 and 28' and extending longitudinally in the same direction as the axle 15 are braces 40 and 40. One brace 40 is supported by and connects the upper end of each of the perpendicular sections 28 disposed on one side of the longitudinal extension of the axle 15 while the other brace 40' is identically attached to each perpendicular section 28' disposed on the opposite side of the axle :15. Extending parallel to the transverse section 26 of the U-shaped brackets 25, with its ends securely attached to braces 40 and 40', are a plurality of supports 41. Each of the supports 41 is a substantially flat rectilinear metal piece which has two annular openings 42 formed therein.

concentrically mounted within each of the openings 42 in the supports 411, is an anode 43. As best shown in FIG. 3 the anode 43 consists essentially of a hollow lead cylinder 44 which has a plurality of cylindrical openings 45 extending through the walls thereof. The cylinder 44 seats on and is closed at its lower end by a stepped cylindrical disc 46. The upper portion 47 of the disc 46 has a diameter substantially equal to the inside diameter of the cylinder 44, so that the lower end of the cylinder 44 circumferentially surrounds the upper portion 47 of the disc 46. The lower portion 48 of the disc 46 has a diameter greater than the upper portion 4-7 and the increased diameter of the lower portion 48 forms a shoulder 49 upon which the cylinder 44 seats. The cylindrical disc 46 is preferably made from a resinous plastic material or the like which is electrically nonconductive.

The cylinder disc 46 sets flush on a titanium plate 50. Titanium has proven very desirable due to its peculiar behavior when immersed in a chromic acid solution whereby it does not function as an electrode. Hence, in the instant embodiment due to this characteristic, current will not flow from the plate St to the bottom of the support 41 or to the perpendicular supports 28 and 28' both of which are negatively charged. As a result there will not be any accidental plating of chromium in these members as is usually the case. Furthermore by including the titanium plate in the construction of the anode as shown, substantially all current flow from the cylinder 44 to the bottom of the support 41 is prevented, and therefore substantially all accidental plating is averted.

The titanium plate 50 is substantially square in shape and is electrically connected and secured to the cylinder 4-4 by means of a weld 51 which encompasses the lower end of the cylinder 44, the disc 46 and is connected to the titanium plate 56. The titanium plate 50 is supported by, but electrically insulated from support 41 by means of an annular collar 52. The collar 52 is substantially cylindrical in shape and encompasses but is spaced from the lower end of the cylinder 44 and the weld 51. The annular collar 52 which is constructed from a suitable electrically nonconductive material has an inside diameter slightly less than the diameter of the openingformed in support 41 with an outside diameter substantially equal to the width of the titanium plate 50. An upper portion 53 of the collar 52 has an outside diameter substantially equal to the diameter of the opening in the support 41 and is circumferentially surrounded thereby. By providing an insulating material between the edge of the diameter of the opening in the support 5-1 and the cylinder 44, plating of this edge portion is prevented. Extendingthrough the sides of the collar 52 are a plurality of openings 54. The plate 50 and the collar 52 are secured to the support 41 by means of bolts 55 which are preferably constructed from a resinous plastic or some other electrically nonconductive material. Another alternative of insuring that there will be no transfer of current from the plate 50 to the support 41 is to position an insulating sleeve about that portion of the bolt which would ordinarily contact the plate and to provide an insulating washer between the head of the bolt 55 and the plate. An insulated electrical conductor 56 is connected to one of the bolts 55 by means of a titanium connector 57 and is connected at its opposite end to the positive pole 26 of the axle 15 such that the titanium plate 50 and ultimately the cylinder 44 is positively charged.

The upper end of the lead cylinder 44 is substantially closed by means of a second plastic disc 58 similar in construction to the first disc 46 in that it has a stepped cylindrical shape. The lower portion 59 of the second disc has a diameter substantially equal in diameter to the inside diameter of the cylinder 44 and an upper portion 60 with a diameter substantially equal to the outside diameter of the cylinder 44 and seats flushly thereon. Extending vertically through substantially the center of the second disc 58 is a cylindrical bore 61. A dowel 62 extends horizontally through the second disc 58 with each end thereof disposed within the wall of the cylinder 44 thereby securing the second disc 58 to the top of the cylinder 44.

Referring now to FIG. 1, in the instant embodiment a workpiece 63 is shown which is a cylinder for a combustion engine and the inner wall of the cylinder within which a piston will reciprocate is the surface to be plated. In order to uniformly plate the inner walls of the cylinder it is imperative that the workpieces be mounted concentrically about the anode 43. As a result aligning pins 64 and 64' which extend vertically upward from the support 41 are included in the apparatus of this embodiment. As shown in FIG. 2 there are holes 65, 66 and 67 along a diameter line into which each pin 64- and 64' may be inserted depending upon the workpiece 63 to be plated.

Extending vertically from both ends of each support 41 is a clamp 72. The clamp 72 consists of a handle portion 73 pivotally mounted at one end on an upright member 74. Also pivotally connected to the upright member 74 is an arm 75. A link 76 is pivotally connected to the handle 73 and the arm thereby linking these two elements. An adjustable screw 77 is included at the end of the arm 75 and as shown in FIG. 1 is movable normal to the arm 75 in a plane toward the top of the workpiece 63 when the lever assembly 72 is in its locking position. The clamp 72 can be moved from its locking position by lifting the handle 73 until it lies at a slight angle above the substantially horizontal plane in which the arm 75 as shown is disposed. The arm 75 is now unlocked and is free to be swung approximately 180 about its pivotal mounting thereby leaving the workpiece 63 unobstructed and able to be removed. After a new workpiece is loaded on the support 41 the handle 73 is again lifted and the arm is swung into its horizontal position at which time the handle is thrust downward, thereby locking the arm in this position.

Disposed between each of the anodes 43, and securely mounted on the support 41 by a suitable attaching means 73 is a rectangular dividing plate 79. Also mounted on one end of the axle 15 as shown in FIG. 2 is a lever 80 which extends normal to the longitudinal extension of the axle 15 and provides means by' which the rack 19 may be rotated.

In operation the rack 10 is initially in the position shown in FIG. 1. The workpieces 63 are inserted over the anodes 43 and in this embodiment are aligned concentrically about the lead cylinder 44 by means of the pins 64 and 64 which are inserted into suitable guide holes included on each workpiece. The clamp 72 is then moved from its open position to its closed position operating as described above, such that each workpiece 7 t) is securely maintained on support 41.

The operator using the lever 80 or any other suitable means and aided by the counterweight 36, rotates the axle 15 within the bearings 13 and 13' until the rack 14) is in the position shown in FIG. 4. As shown, the workpieces 63 are submerged into the bath of electrolyte 14 which in this embodiment is a chromic acid solution and electroplating begins.

By this immersion, the electrolyte 14 has entered the cathode 43 through openings 54 formed on the collar 52 and has circulated down and around the lead cylinder 44 between the workpiece 63 (as indicated in FIG. 3) and has entered into the lead cylinder 44 by means of openings 45 formed on the sides of the lead cylinder 44 and the bore 59 formed in the top thereof. Soon after emersion, the electrolyte 14 has completely circulated through the cathode 43 and any air trapped therein has escaped through the openings 54. It is to be noted that the openings 45 formed in the lead cylinder 44 not only allow the electrolyte to circuate therethrough but also provide a means through which the gas which is deposited on the walls of the cylinder during the plating operation may escape and through which electrolyte may circulate so that there is always chromic acid solution maintained between the anode and the surface to be plated.

The axle i5 is connected to a suitable source of electricity by means of terminals 21 and 22. As shown in FIG. 4 the upper portion 19 of the bipolar axle 15 is negatively charged. This negative charge is transferred through the transverse section 26 of the U-shaped brackets 25 up the perpendicular supports 28 and 23 thereby charging the braces 40 and 4t) and ultimately the support 41 negatively. Hence when the workpiece 63 is flushed on the support 41 it also is negatively charged and becomes the cathode in the electroplating apparatus. The lower portion 20 of the axle is simultaneously positively charged and this charge is transferred to the anode 43 by means of electrical conductors 56. Each of the conductors 56 transfers the positive charge to the titanium plate th, which in turn transfers this charge to the cylinder 44 by means of the weld 51 such that it is rendered anodic. As described above, electrolyte 14 is maintained between the outer periphery of the negatively charged cylinder 44 and the positively charged workpiece 70 (as indicated in FIG. 3), metallic chromium is extracted from the electrolyte 14 and is deposited upon the inner wall of the workpiece 63. Oxygen gas is deposited at the anode i3 and is liberated therefrom by the circulation of the electrolyte as described above. Once a suitable plate has been deposited, the rack is rotated to the position shown in FIG. 1 emerging the anodes 43 and workpieces 63 from the electrolyte and thereby stopping the electroplating operation. The plated workpieces 63 are then removed, replaced by unplated ones and the preceding operations are repeated.

As evidenced by the above description, the rotatable plating rack facilitates plating of workpieces such as cylinders, which commonly present difiicul-t handling problems. Moreover due to its unique construction including relative compactness of the apparatus, its ease of rotation and the advanced cathode design whereby accidental plating is substantially prevented, economy of operation an advantage not heretofore mentioned will be self-evident to those familiar with electroplating operations.

We claim:

1. A rotatable plating rack for use in combination with a bath of electrolyte to simultaneously plate at least one workpiece comprising a bipolar electrically conductive axle mounted for rotation about a fixed axis, bearings in which said axle is rotatable, a bracket assembly rigidly attached to said axle and rotatable therewith, said bracket assembly being electrically connected to one pole of said axle, at least one anode mounted on said bracket assembly in such position that it is submerged into and emerged from the electrolyte as said axle is rotated, said anode being insulated from said bracket assembly, said workpiece being adapted to be mounted on said bracket assembly in electrical contact therewith, electrical conductor means for connecting said anode to the other pole of said axle, and means for rotating said axle.

2. A rotatable plating rack for use in combination with a chromium electroplating bath to simultaneously plate at least one workpiece comprising a bipolar electrically conductive axle mounted for rotation about a fixed axis, hearings in which said axle is rotatable, a bracket assembly rigidly attached to said axle and rotatable therewith, said 'bracket assembly being electrically connected to one pole of said axle, an anode-supporting plate mounted on said bracket assembly, at least one anode mounted on said plate in such position that it is submerged into and emerged from the electrolyte as said axle is rotated, said anode being insulated (from said bracket assembly and being electrically connected to the other pole of said axle, said workpiece being adapted to be mounted on said bracket assembly in electrical contact therewith, and means for rotating said axle.

3. A rotatable plating rack for use in combination with a bath of eletcrolyte to simultaneously plate a plurality of workpieces comprising a bipolar electrically conductive axle, bearings in which said axle is rotatable, a bracket assembly rigidly attached to said axle and rotatable therewith, said bracket assembly electrically connected to one pole of said axle, a plurality of anodes mounted on said brackets in such position that they are submerged into and emerged from the electrolyte as said axle is rotated, said anodes being insulated from said bracket assembly, said workpieces being adapted to be mounted on said bracket assembly, clamp means on said bracket for maintaining said workpieces on said bracket assembly in electrical contact therewith and in proximal relationship with said anodes, a source of electricity, electrical conductor means for connecting said cathodes to the other pole of said axle, a counterweight secured to said axle for counterbalancing the weight of said bracket assembly and thereby aiding in rotation of said axle, and means for rotating said axle.

4. A rotatable plating rack for use in combination with a bath of electrolyte to simultaneously plate the inner walls of at least one substantially cylindrical workpiece comprising a bipolar electrically conductive axle, bearings in which said axle is rotatable, a bracket assembly rigidly attached to said axle and rotatable therewith, said bracket assembly being electrically connected to one pole of said axle, at least one cylindrical anode mounted on said bracket assembly in such position that it is submerged into and emerged from the electrolyte as said axle is rotated, said anodes being insulated from said bracket assembly, said bracket assembly being adapted to receive and hold said workpiece concentrically about said anode, electrical conductor means for connecting said anode to the other pole of said axle, and means for rotating said axle.

5. A rotatable plating rack for use in combination with a bath of electrolyte to simultaneously plate the inner walls of a plurality of substantially cylindrical workpieces comprising a bipolar electircally conductive axle, bearings in which said axle is rotatable, a bracket assembly rigidly attached to said axle and rotatable therewith, said bracket assembly being electrically connected to one pole of said axle, a plurality of cylindrical anodes mounted on said brackets in such position that they are submerged into and emerged from the electrolyte as said axle is rotated, said anodes being insulated from said bracket assembly, said bracket assembly being adapted to receive and hold said workpieces concentrically about said anodes and to make electrical contact with them, clamp means on said bracket for securing said workpieces on said bracket assembly in proximal relationship with said anodes, electrical conductor means for connecting said anodes to the other pole of said axle, a counterweight secured to said axle for counterbalancing the weight of said bracket assembly and said workpieces and thereby aiding rotation of said axle, and means for rotating said axle.

6. A rotatable plating rack for use in combination with a bath of electrolyte to simultaneously plate the inner walls of a plurality of workpieces comprising a bipolar electrically conductive axle, said axle consisting of a first metallic bar adapted to be positively charged, a second metallic bar adapted to be negatively charged, a length of insulation material disposed between said first and second bars, and binding means for holding said bars and insulation material securely together, bearings in which said axle is rotatable, a plurality of brackets rigidly connected to the first metallic bar of said axle and rotatable therewith, a plurality of supports connected to said brackets and spaced from said ax le, a plurality of plates connected to but insulated from said supports, a cylindrical anode mounted on and electrically connected to each of said plates in such position that they are submerged into and emerged'from the electrolyte as the axle is rotated, said bracket assembly being adapted to receive and hold said workpieces concentrically about said anodes, said anode being spaced from said cylindrical workpiece to permit electrolyte to enter therebetween, alignment means for maintaining said workpieces in proper position on said support, electrical conductor means for connecting said plate to the second metallic bar of said axles, a counterweight secured to said axle to counterbalance the Weight of said bracket assembly and said workpieces and thereby aid in rotation of said axle, and means for rotating said axle.

7. A rotatable plating rack for use in combination with a bath of electrolyte to simultaneously plate a plurality of workpieces comprising a bipolar electrically conductive axle, said axle consisting of a first metallic bar adapted to be positively charged, a second metallic bar adapted to be negatively charged, a length of insulation material disposed between said positive and negative lengths, and binding means for holding said bars and insulation securely together, bear ngs in which said axle is rotatable, a plurality of brackets rigidly connected to the first metallic bar of said axle and rotatable therewith, a plurality of supports electrically connected to said brackets and spaced from said axle, a plurality of titanium plates connected to but insulated from said supports, an anode mounted on and electrically connected to each of said titanium plates in such position that they are submerged into and emerged from the electrolyte as the axle is rotated, said anodes consisting of substantially hollow cylinders with perforations formed in the sides thereof, each of said anodes being closed at its lower end and partially open at its upper end and mounted on said plate so that the electrolyte can circulate through the anode, said cylindrical workpieces being adapted to be mounted on said support concentrically about said anode and electrically connected to said support, clamp means for clamping said workpieces on said support with said anode spaced from said cylindrical workpiece to permit electrolyte to enter therebetween, electrical means for connecting said titanium plate to the second bar of said axle, a counterweight secured to said axle to counterbalance the weight of said bracket assembly and said workpieces and thereby aid in rotation of said axle, and means for rctatin g said axle.

8. In a rotatable plating rack having a bipolar clcctrically conductive axle, means for rotatably supporting said axle comprising bearings through which said axle extends and journals of non-conducting resinous plastic material rigidly secured to and surrounding said axle along that portion which is disposed within said bearings, said journals being cylindrical in shape and rotatable in said bearings, whereby said journals freely turn in said bearings to enable rotation of said axle and coincidentally insulate the axle against transfer of current to the bearings or between poles of said axle.

References Cited in the file of this patent UNITED STATES PATENTS 1,563,041 Purinton Nov. 24, 1925 1,726,308 ONeill Aug. 27, 1929 2,362,474 Elsenheimer Nov. 14, 1944 2,654,707 Satfel Oct. 6, 1953 2,722,513 Clark Nov. 1, 1955 2,760,929 Shepard et al Aug. 28, 1956 2,839,463 Vellas et al June 17, 1958 3,023,154 Hough et al Feb. 27, 1962 FOREIGN PATENTS 1,043 Great Britain Feb. 27, 1883 of 1883 608,462 Great Britain Sept. 15, 1948 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 lO8 O56 October 22 1963 Louis W. Raymond et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column l. line 56 for- "it' read is column 3, line l5 for "sets" read seats column 4 line 68, for "circuate" read circulate column 5 line 7,, for "flushed" read flush column 6, line 35, for "electircally" read electrically Signed and sealed this 5th day of May 1964.

(SEAL) Attest:

ERNEST W, SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A ROTATABLE PLATING RACK FOR USE IN COMBINATION WITH A BATH OF ELECTROLYTE TO SIMULTANEOUSLY PLATE AT LEAST ONE WORKPIECE COMPRISING A BIPOLAR ELECTRICALLY CONDUCTIVE AXLE MOUNTED FOR ROTATION ABOUT A FIXED AXIS, BEARINGS IN WHICH SAID AXLE IS ROTATABLE, A BRACKET ASSEMBLY RIGIDLY ATTACHED TO SAID AXLE AND ROTATABLE THEREWITH, SAID BRACKET ASSEMBLY BEING ELECTRICALLY CONNECTED TO ONE POLE OF SAID AXLE, AT LEAT ONE ANODE MOUNTED ON SAID BRACKET ASSEMBLY IN SUCH POSITION THAT IT IS SUBMERGED INTO AND EMERGED FROM THE ELECTROLYTE AS SAID AXLE IS ROTATED, SAID ANODE BEING INSULATED FROM SAID BRACKET ASSEMBLY, SAID WORKPIECE BEING ADAPTED TO BE MOUNTED ON SAID BRACKET ASSEMBLY IN ELECTRICAL CONTACT THEREWITH, ELECTRICAL CONDUCTOR MEANS FOR CONNECTING SAID ANODE TO THE OTHER POLE OF SAID AXLE, AND MEANS FOR ROTATING SAID AXLE. 